Background: Variations in referral rates exist, at GP and practice level. Although the National Institute for Clinical Excellence is to produce referral guidelines, it is unclear if this variation requires regulation. A critical review of the literature on variation in referral rates was undertaken to see if existing evidence could inform the debate.
Objectives: The aim of this study was to describe the variation in referral rates; to identify likely explanatory variables; and to describe the effect of GPs' decision making on the referral process.
Methods: Six bibliographic databases, the Cochrane Library, the NHS Centre for Reviews and Dissemination, and the National Research Register were searched.
Results: Patient characteristics explain <40% of the observed variation; practice and GP characteristics <10%. The availability of specialist care does affect referral rates, but its influence on the observed variation of referral rates is not known. Intrinsic psychological variables are important. GPs who are less tolerant of uncertainty or who perceive serious disease to be a more frequent event may refer more patients. There is a lack of consensus about what constitutes an appropriate referral, and the use of guidelines has had only limited success in altering referral behaviour.
Conclusions: Variation in referral rates remains largely unexplained. Targeting high or low referrers through clinical guidelines may not be the issue. Rather, activity should concentrate on increasing the number of appropriate referrals, regardless of the referral rate. Pressure on GPs to review their referral behaviour through the use of guidelines may reduce their willingness to tolerate uncertainty and manage problems in primary care, resulting in an increase in referrals to secondary care. The use of referral rates to stimulate dialogue and joint working between primary and secondary care may be more appropriate.